How to read compass on nodemcu8266

[wasyamsudin]

hi, let me ask.
I have a project to simulate the heading of a compass and the movement of two dc motors. when i operate it on arduino nano/uno, no problem. but when I operate it on nodemcu, somehow the compass readings don't appear on the serial monitor. does anyone know about SDA or SCL on nodemcu? this is the code i use

#include <TinyGPS++.h>
#include <SoftwareSerial.h>
#include <Wire.h>
#include <QMC5883LCompass.h>
//#include <ESP8266WiFi.h>

#define RX_PIN 2
#define TX_PIN 3
#define LED_PIN 13
#define GPS_BAUD 9600
#define WAYPOINT_THRESHHOLD 3
int LEFT_MOTOR[3] = {8, 4, 5};
int RIGHT_MOTOR[3] = {9, 6, 7};

TinyGPSPlus gps;
//const char* ssid = "wifi kami"; //ssid of your wifi
//const char* password = "cipicung"; //password of your wifi
//float latitude , longitude;
//int hour , minute , second;
//String time_str , lat_str , lng_str;
//int pm;
//WiFiServer server(80);

int wp = 0;
bool selesai = false;

QMC5883LCompass compass;

SoftwareSerial ss(RX_PIN, TX_PIN);


int calcLeftMotor(double relBearing) {
  if (relBearing > 0)
    return 255;
  else
    return 1.425 * relBearing + 255;
}

int calcRightMotor(double relBearing) {
  if (relBearing <= 0)
    return 255;
  else
    return -1.425 * relBearing + 255;
}

//KALAU NGASIH RAW DATA MAGNETIK (if give raw magnetic data)
double calcHeading (int x, int y) {
  return -atan2(x, y) * 180 / 3.141592654;
}

void setup() {
  Serial.begin(9600);
  ss.begin(GPS_BAUD);
  pinMode(LED_PIN, OUTPUT); //LED

  pinMode (LEFT_MOTOR, OUTPUT);
  pinMode (RIGHT_MOTOR, OUTPUT);

//  WiFi.begin("wifi kami", "cipicung"); //connecting to wifi
//  while (WiFi.status() != WL_CONNECTED)// while wifi not connected
//  Serial.println("");
//  Serial.println("WiFi connected");
//  server.begin();
//  Serial.println("Server started");
//  Serial.println(WiFi.localIP()); 
  
  Serial.println("Menuju Waypoint");

  //init compass
  compass.init();
}

void loop() {
  double targetLat[] = {-6.992833};
  double targetLon[] = {107.642863};
  int jmlWP = sizeof(targetLat)/4;

  while (ss.available() > 0)
    gps.encode(ss.read());

  if(wp >= jmlWP) 
    selesai = true;

  double dist = 0;
  if (gps.location.isValid()) {
    dist = distance(targetLat[wp], targetLon[wp], gps.location.lat(), gps.location.lng());
    Serial.print("distance to target: ");
    Serial.println(dist);


    double bearing = 0; //target angle
    compass.read(); // reads from compass

    double heading = calcHeading(compass.getX(), compass.getY());
    double relBearing = bearing - heading;

    int leftSpeed = map(calcLeftMotor(relBearing),0,255,130,150);
    int rightSpeed = map(calcRightMotor(relBearing),0,255,130,150);

    if(selesai){
      digitalWrite(LEFT_MOTOR[1], 0);
      digitalWrite(LEFT_MOTOR[2], 0);
      analogWrite(LEFT_MOTOR[0], 0);
      // RIGHT_MOTOR
      digitalWrite(RIGHT_MOTOR[1], 0);
      digitalWrite(RIGHT_MOTOR[2], 0);
      analogWrite(RIGHT_MOTOR[0], 0);      
    }else if (dist > WAYPOINT_THRESHHOLD) {
      //LEFT_MOTOR
      digitalWrite(LEFT_MOTOR[1], 1);
      digitalWrite(LEFT_MOTOR[2], 0);
      analogWrite(LEFT_MOTOR[0], leftSpeed);
      // RIGHT_MOTOR
      digitalWrite(RIGHT_MOTOR[1], 0);
      digitalWrite(RIGHT_MOTOR[2], 1);
      analogWrite(RIGHT_MOTOR[0], rightSpeed);
    }else if(dist <= WAYPOINT_THRESHHOLD){
      wp++;
    }
    //    if (dist < WAYPOINT_THRESHHOLD)
    //      digitalWrite(LED_PIN, HIGH);
    //
    //    if (dist > WAYPOINT_THRESHHOLD)
    //      digitalWrite(LED_PIN, LOW);

    Serial.print(" Heading: "); Serial.println(heading);
    Serial.print("Left: "); Serial.print(leftSpeed); Serial.print(" Right: "); Serial.println(rightSpeed);
    Serial.println(" ");
delay (1000);
  }
}



double distance(double lat1, double lon1, double lat2, double lon2)
{
  // Conversion factor from degrees to radians (pi/180)
  const double toRadian = 0.01745329251;

  // First coordinate (Radians)
  double lat1_r = lat1 * toRadian;
  double lon1_r = lon1 * toRadian;

  // Second coordinate (Radians)
  double lat2_r = lat2 * toRadian;
  double lon2_r = lon2 * toRadian;

  // Delta coordinates
  double deltaLat_r = (lat2 - lat1) * toRadian;
  double deltaLon_r = (lon2 - lon1) * toRadian;

  // Distance
  double a = sin(deltaLat_r / 2) * sin(deltaLat_r / 2) + cos(lat1_r) * cos(lat2_r) * sin(deltaLon_r / 2) * sin(deltaLon_r / 2);
  double c = 2 * atan2(sqrt(a), sqrt(1 - a));
  double distance = 6371 * c * 1000;

  return distance;

}

this is what the serial monitor looks like if the program is run on an arduino nano/uno

[martinius96]

And how you connect your compass to NodeMCU?
Were you using its hardware SDA and SCL pins?

[wasyamsudin]

yes, I connected it to pins D2 for SDA and D1 for SCL. I'm referring to the reference from the datasheet image I found on the internet. if i'm wrong please correct me

[martinius96]

You are correct. It should work.
Is compilation working? If yes, was begin of communication with address of your compass successful?

[wasyamsudin]

everything is fine when using nano/uno. but when using nodemcu, the serial monitor only displays like this.

this also happens when using coding from the internet to display the heading of the compass, where the compass reading does not seem to respond to the compass movement rotated by the user